1. Field of the Invention
The present invention relates to an image processing method, an image processing program and an image processing apparatus, and a playback method, a playback program and a playback apparatus, which are suitably employed for converting the frame frequency of an image signal.
2. Description of the Related Art
In recent years, with realization of digital high vision broadcasting and the like, a progressive-scan video signal having the frame frequency of 59.94 Hz, from which a higher definition image can be projected, has come to be frequently employed for the format of a video signal, instead of an existing interlace-scan video signal having the frame frequency of 29.97 Hz (in the case of NTSC (National Television System Committee)). On the other hand, for example, movie images have been traditionally created using optical film, which becomes a progressive-scan video signal at 24 frames per second, i.e., with the frame frequency of 24 Hz.
Processing configured to generate a video signal having the frame frequency of 59.94 Hz from a video signal having the frame frequency of 24 Hz is realized by converting each frame of a video signal having the original frame frequency of 24 Hz into a video signal having the frame frequency of 60 Hz once, and then converting this video signal of 60 Hz into a video signal having the frame frequency of 59.94 Hz.
In the event of converting a video signal having the frame frequency of 24 Hz into a video signal having the frame frequency of 59.95 Hz (60 Hz), processing is performed wherein a video signal having the frame frequency of 24 Hz is alternately converted into the three frames or two frames of a video signal having the frame frequency of 60 Hz with a predetermined conversion pattern, which is referred to as 3-2 pulldown (or 2-3 pulldown).
With International Publication No. 04/032494 pamphlet, a technique has been described wherein a video signal having the frame frequency of 24 Hz based on a film material is converted into a progressive-scan video signal having the frame frequency of 59.94 Hz by the 3-2 pulldown processing.